Question: Simplify the following expression: $y = \dfrac{3a + 9}{7} \div \dfrac{9a}{3}$
Explanation: Dividing by an expression is the same as multiplying by its inverse. $y = \dfrac{3a + 9}{7} \times \dfrac{3}{9a}$ When multiplying fractions, we multiply the numerators and the denominators. $y = \dfrac{ (3a + 9) \times 3 } { 7 \times 9a}$ $y = \dfrac{9a + 27}{63a}$ Simplify: $y = \dfrac{a + 3}{7a}$